This invention relates to a device and method for inflating and deflating a balloon used to protect the cerebrum against emboli during carotid stenting, where the balloon is carried on a guide wire and where the inflation can be accomplished without the need of a port on the guide wire. Coaxial systems may be applied over the guide wire, because the outside of the guide wire is of a smooth surface with no ports.
The device comprises a guide wire, having a lumen inside the guide wire. The guide wire has one end occluded and the other end open, and has a balloon at the occluded end. The guide wire has two or three orifices, each extending from the exterior of the guide wire to reach the lumen of the guide wire. Thus, the lumen of the guide wire is connected to the inside of the balloon through these orifices. The area of the guide wire with the orifices is covered by a silicon or polyurethane balloon. A core segment is inserted into the open end of the guide wire to the closed end of the guide wire before the orifices on the guide wire are covered by a balloon. The core segment may be removed from the guide wire when the open end of the guide wire is inside a basin full of normal saline mixed with non-ionic contrast media solution. When the core segment is removed, it creates a vacuum inside the lumen of the guide wire which is filled immediately with the solution. Then, the core segment is gently advanced until the balloon is fully distended. Through a locking mechanism, the core segment is kept in position during the time needed for the procedure. Coaxial systems, such as balloon catheter and stent delivery systems, may be applied over the guide wire. After the procedure which may generate emboli is completed, the core segment is unlocked and retrieved and the balloon is thereby deflated.
Although traditionally conventional open surgery has been used in treatments of vascular diseases, such as stenosis of the carotid artery, nowadays endovascular treatments are gaining acceptance. Endovascular treatments are carried out in the lumen of the vascular duct and have the advantage of being less aggressive than the conventional open surgery posing less risk to the patient because it can be performed under limited local anesthesia and without surgery.
Where there is stenosis of an artery, such as the common carotid artery, the internal carotid artery or the external carotid artery, the vascular wall of the artery is affected by a pathologic narrowing that prevents the blood stream from flowing normally. A common treatment consists of endovascular angioplasty, where an angioplasty balloon is inserted into the lumen of the blood vessel and the angioplasty balloon is expanded in order to expand the area having the stenosis. If necessary, a stent is placed to cover the afflicted area.
Balloon angioplasty and stenting are a rapidly growing field in vascular intervention. The main and dreadful complication of carotid balloon angioplasty and stenting is cerebral embolization. Several studies have shown that the incidence of embolization is high during these procedures.
The problem in this treatment is that emboli can be formed during the course of the procedure which can rapidly reach the brain and cause injury and death. Emboli are especially prone to be formed when the angioplasty balloon is expanded or while the stent is placed and expanded.
Investigators, such as Jack Theron, used a balloon to prevent particles generated in the affected area from reaching the brain. U.S. Pat. No. 5,833,650 of inventor Imran, entitled Catheter Apparatus and Method for Treating Occluding Vessells, issued Nov. 10, 1998. The Imran patent described a system to achieve cerebral protection using a guide wire and inflated balloons, which allowed the advancement over the guide wire of a coaxial system of balloon angioplasty catheters and stent delivery systems. The use of occlusion balloons to protect the brain during carotid balloon angioplasty and stenting (CBAS) was presented publicly by Theron in Milwaukee in 1994.
Difficulty exists in keeping the occlusion balloon inflated and undisturbed when changing the coaxial systems. The ports with valves on a guide wire prevent advancement of coaxial systems, that very often need to be changed. For instance, different balloon diameters may be needed in the procedure. Sometimes, one balloon may need to be replaced with a balloon of a different diameter. Systems to deploy a stent and systems to expand a stent with a balloon also may require coaxial systems. The presence of a port on the guide wire would obligate the operator to deflate and remove the guide wire every time he needed to exchange the coaxial system, such as, for example, either to use a different balloon diameter catheter or to advance a delivery system for stent deployment.
Therefore, there is needed in the art a device and method that allows for the inflation and deflation, without the need of a port on the guide wire, of a balloon carried on a guide wire. There is needed a device and method which allow for the use of coaxial systems to be placed over the guide wire to allow for the use and placement of instrumentation needed during the medical procedure without the necessity of deflating the balloon and removing the guide wire.
The present invention recognizes that a balloon situated on a hollow guide wire, where the hollow guide wire permits insertion of a core segment into the lumen of the guide wire, will allow for easy and convenient inflation and deflation of the balloon while permitting coaxial systems to be introduced over the guide wire. Thus, the present invention allows for the rapid exchange of coaxial systems without the need to disconnect or connect ports which in prior art have been attached to the guide wire.
The invention comprises a hollow guide wire with a plurality of orifices extending from the exterior of the guide wire to its lumen, an attached balloon which covers the orifices and a core segment. The core segment may be inserted into the lumen of the guide wire and then removed from the lumen of the guide wire when the open end of the guide wire is inserted in a solution. The core segment is sized to fit snugly within the lumen of the guide wire and serves as a piston to inflate the guide wire balloon.
The guide wire is provided with a closed end and an open end which form a tubular body having an internal lumen. Near the closed end of the guide wire there is a guide wire balloon, which may be expandable against the vascular duct to occlude the blood flow.
The guide wire with attached guide wire balloon have a low profile allowing the insertion and advancement of coaxial balloon catheters and stent delivery systems over the guide wire without disturbing the inflated guide wire balloon.
In use, the operator takes the guide wire with the core segment positioned inside the lumen of the guide wire and with the guide wire balloon in its uninflated position on the guide wire, and inserts the closed end of the guide wire with the attached guide wire balloon into the patient through methods known in the art, such as percutaneously into the femoral artery. Then, the guide wire balloon is advanced through the vessel and positioned at the appropriate location in the patient. The open end of the guide wire is inserted inside a solution. A solution of normal saline mixed with non-ionic contrast media may be used. In particular, a solution consisting of 50% normal saline and 50% non-ionic contrast media may be used. The core segment is removed from the lumen of the guide wire with the open end of the guide wire inserted within the solution. The solution fills the lumen of the guide wire. Then, the core segment is gently advanced toward the guide wire balloon until the guide wire balloon is fully dilated. The guide wire balloon is thus expanded against the vascular walls. Once the guide wire balloon is inflated, the core segment is fixed in position within the guide wire by a locking mechanism which does not increase the profile of the guide wire. Therefore, the advancement of coaxial systems over the guide wire is allowed. Coaxial systems may be exchanged without the need to deflate the guide wire balloon.